The present invention relates to a pull rope starting device for an internal combustion engine wherein the rope starting device includes a freewheel coupling having a driving coupling part formed as part of the rope pulley, and a driven coupling part attached to the flywheel of the engine.
In known starting devices of the aforementioned type the freewheel coupling comprises a cylindrical ratchet wheel and two pawls adapted to engage the ratchet wheel at diametrically opposite sides of the ratchet wheel. The pawls are pivotally attached to the flywheel of the engine and actuated by a resilient force in order to normally engage the ratchet wheel. When the engine has started, the pawls are acted upon by centrifugal forces created by rotation of the flywheel which counteracts the resilient force, thus releasing the pawls from engagement with the ratchet wheel.
To reduce manufacturing expense, the ratchet wheel and the pulley are preferably made from one piece of plastic material. However, in order to assemble the freewheel coupling which incorporates a cylindrical ratchet wheel, it is necessary to bevel the pawls. Beveling the pawls allows the pawls to be mounted around the ratchet wheel against the action of the mentioned resilient force. Unfortunately, beveling the pawls reduces the area of engagement between the pawls and the ratchet wheel. The reduced area of engagement between the pawls and the ratchet wheel has resulted in problems in manufacturing a pulley and ratchet wheel assembly from plastic material which is strong enough to obtain a starting device with the desired reliability and durability.